Hitting a New Low: The Unique 28 h Cessation of Accretion in the TESS Light Curve of YY Dra (DO Dra)

Abstract

We present the Transiting Exoplanet Surveying Satellite (TESS) light curve of the intermediate polar YY Draconis (YY Dra, also known as DO Dra). The power spectrum indicates that while there is stream-fed accretion for most of the observational period, there is a day-long, flat-bottomed low state at the beginning of 2020 during which the only periodic signal is ellipsoidal variation and there is no appreciable flickering. We interpret this low state to be a complete cessation of accretion, a phenomenon that has been observed only once before in an intermediate polar. Simultaneous ground-based observations of this faint state establish that when accretion is negligible, YY Dra fades to $g=17.37\pm 0.12$, which we infer to be the magnitude of the combined photospheric contributions of the white dwarf and its red dwarf companion. Using survey photometry, we identify additional low states in 2018-2019 during which YY Dra repeatedly fades to -- but never below -- this threshold. This implies relatively frequent cessations in accretion. Spectroscopic observations during future episodes of negligible accretion can be used to directly measure the field strength of the white dwarf by Zeeman splitting. Separately, we search newly available catalogs of variable stars in an attempt to resolve the long-standing dispute over the proper identifier of this system.

arXiv comment12 pages, 4 figures, submitted to the Astronomical Journal and reviewed favorably

References in corpus (25)

• Astropy: A Community Python Package for Astronomy
• The Transiting Exoplanet Survey Satellite
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• The Catalina Surveys Periodic Variable Star Catalog
• The ASAS-SN Catalog of Variable Stars I: The Serendipitous Survey
• The ASAS-SN Catalog of Variable Stars II: Uniform Classification of 412,000 Known Variables
• Measuring the masses of magnetic white dwarfs: A NuSTAR Legacy Survey
• Magnetically gated accretion in an accreting 'non-magnetic' white dwarf
• The Rise and Fall of the King: The Correlation between FO Aquarii's Low States and the White Dwarf's Spindown
• Quasi-periodic oscillations in the TESS light curve of TX Col, a diskless intermediate polar on the precipice of forming an accretion disk
• PALOMA: A Magnetic CV between Polars and Intermediate Polars
• Return of the King: Time-Series Photometry of FO Aquarii's Initial Recovery from its Unprecedented 2016 Low State
• An accreting white dwarf displaying fast transitional mode switching
• X-ray observations of FO Aqr during the 2016 low state
• Multiple time scales in cataclysmic binaries. The low-field magnetic dwarf nova DO Draconis
• When the disc's away, the stars will play: dynamical masses in the nova-like variable KR Aur with a pinch of accretion
• The effects of tidally induced disc structure on white dwarf accretion in intermediate polars
• The true nature of Swift J0746.3-1608: a possible Intermediate Polar showing accretion state changes
• Rapid bursts of magnetically gated accretion in the intermediate polar V1025 Cen
• Optical spectra of FO Aquarii during low and high accretion rates
• New observations of DW Cnc: where is the 38 min signal?
• The Magnetic Cataclysmic Variable LSQ1725-64

Cited by in corpus (6)

• The Orbital Period vs. Absolute Magnitude Relationship of Intermediate Polars: Implications for Low States and Outbursts
• Unveiling $\delta$ Scuti and $\gamma$ Doradus Hybrid Pulsation of HD 53166 and HD 53349 Plus Rich Frequencies in HD 52788 -- Catalogs of 70552 $\delta$ Sct and 8080 $\gamma$ Dor
• Kepler K2 and TESS observations of two magnetic cataclysmic variables: The new asynchronous polar SDSS J084617.11+245344.1 and Paloma
• Short Duration Accretion States of Polars as seen in TESS and ZTF data
• Serendipitous discovery of the magnetic cataclysmic variable SRGE J075818-612027
• Confirmation of SRGt 062340.2-265751 as a nova-like cataclysmic variable with a possible magnetic nature